Mechanical Engineering, Chemical Engineering, University of Washington, Seattle, Washington 98195, USA.
Langmuir. 2012 Nov 27;28(47):16318-26. doi: 10.1021/la302654s. Epub 2012 Sep 6.
Lipid bilayers are biomembranes common to cellular life and constitute a continuous barrier between cells and their environment. Understanding the interaction of engineered nanomaterials (ENMs) with lipid bilayers is an important step toward predicting subsequent biological effects. In this study, we assess the effect of varying the surface functionality and concentration of 10-nm-diameter gold (Au) and titanium dioxide (TiO(2)) ENMs on the disruption of negatively charged lipid bilayer vesicles (liposomes) using a dye-leakage assay. Our findings show that Au ENMs having both positive and negative surface charge induce leakage that reaches a steady state after several hours. Positively charged particles with identical surface functionality and different core compositions show similar leakage effects and result in faster and greater leakage than negatively charged particles, which suggests that surface functionality, not particle core composition, is a critical factor in determining the interaction between ENMs and lipid bilayers. The results suggest that particles permanently adsorb to bilayers and that only one positively charged particle is required to disrupt a liposome and trigger the leakage of its entire contents in contrast to mellitin molecules, the most widely studied membrane lytic peptide, which requires hundred of molecules to generate leakage.
脂质双层是细胞膜的基本结构，存在于所有细胞中，是细胞与其周围环境之间的连续屏障。了解工程纳米材料（ENMs）与脂质双层的相互作用是预测随后的生物学效应的重要步骤。在这项研究中，我们使用染料渗漏测定法评估了不同表面功能和浓度的 10nm 直径金（Au）和二氧化钛（TiO(2)）纳米材料对带负电荷的脂质双层囊泡（脂质体）破坏的影响。我们的研究结果表明，带正电荷和负电荷的 Au ENMs 都能诱导脂质体发生渗漏，数小时后达到稳定状态。具有相同表面功能但核心成分不同的带正电荷的颗粒表现出相似的渗漏效应，并且比带负电荷的颗粒导致更快和更大的渗漏，这表明表面功能而不是颗粒核心成分是决定 ENMs 与脂质双层相互作用的关键因素。结果表明，颗粒会永久性地吸附在双层膜上，与只需一个带正电荷的颗粒即可破坏脂质体并引发其内容物全部渗漏形成对比，而研究最广泛的膜裂解肽——蜂毒素分子则需要数百个分子才能引发渗漏。
